In the field of wireless communications, a problem that needs to be addressed relates to allowing mobile stations to continue to communicate when they migrate from their home wireless communication network to a visited wireless communication network. As used herein, the term “migrate” refers to movement of a mobile station from one wireless communication network to another, whereas roaming refers to movement of a mobile station within a wireless communication network. For example, when a mobile station that belongs to a particular wireless communication network migrates to another wireless communication network, the mobile station may be incompatible with the new wireless communication network that it has migrated to. In such situations, it would be desirable to allow a migrated mobile station to continue to communicate with its home wireless communication network over infrastructure equipment of the visited wireless communication network. For example, it would be desirable for a mobile station to be able to establish a connection to its own home wireless communication network from outside the coverage area of the home wireless network by communicating through or “over” another visited wireless communication network. When a mobile station migrates from a wireless communication network, a registration process occurs at the new wireless communication network. Registration refers to identification of a mobile station by a wireless communication network and the exchange of information between the mobile station and the wireless communication network so that so that the mobile station is allowed to join the wireless communication network. In many cases, after being identified, the mobile station must first be authenticated before being allowed to participate in the network.
For example, two types of wireless communication networks include public wireless communication networks, such as the Global System for Mobile Communication (GSM) system, and private mobile radio (PMR) networks, such as TErrestrial Trunked RAdio (TETRA) networks. When a PMR terminal is located in the coverage area of another wireless communication network, such as a GSM network, and registers with that other wireless communication network, the incompatibility of the PMR terminal with the other wireless communication network can prevent the PMR terminal from connecting back to its PMR wireless communication network.
One solution for interconnecting two different types of communication networks is to develop a gateway interconnecting the two communication networks. Development of such a gateway requires that the manufacturers of the infrastructure equipment used in the different communication networks collaborate to standardize the protocols, interfaces, services, and the like that are used to communicate between the two communication networks. In addition, implementation of the gateway may require changes to infrastructure equipment, development of new interfaces, and the like.
As one example, the TETRA standards body is currently standardizing an Inter-System Interface (ISI) that allows mobile stations to use a visited independent TETRA network when required. ISI allows users in one TETRA network to communicate with users in another independent TETRA network. The ISI also provides an ISI gateway that is used to interconnect infrastructure in each TETRA network.
Development of a proprietary gateway for interconnecting two networks (also called Switching and Management Infrastructure (SwMI) in the TETRA standards) can be very costly and time-consuming since the manufacturer of each SwMI must cooperate to standardize the protocols, interfaces, services, and the like that are used to communicate between the two SwMIs. In addition, the ISI gateway may require changes to each SwMI and new interfaces.
In another example, if two equipment manufacturers want to interconnect a TETRA network with a non TETRA network, (for example a GSM network), then they need to collaborate to develop another unique gateway that can interconnect between the TETRA network with the GSM network. Development of another proprietary gateway for interconnecting the two networks will require another standardization effort.
Each time two different types of networks are interconnected this standardization effort must be repeated. It would be desirable to provide a simpler solution that is generally applicable to more than two particular types of communication networks.
Accordingly, there is a need for improved methods, systems and apparatus for interconnecting different types of wireless communication networks.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments described herein so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.